This invention relates to a process for dyeing synthetic fabrics using high-boiling ester solvent media in which a dye or mixture of dyes meeting selected performance and physical criteria is used.
Synthetic fabrics can be dyed rapidly and effectively at elevated temperatures using dyes dissolved in and applied from high-boiling ester-type solvents. Waterless dye compositions for apparel and other thermoplastic articles are described in a series of U.S. patents to Robert B. Wilson, more fully identified below, and exemplified by U.S. Pat. No. 4,581,035. See also U.S. Pat. No. 4,550,579 to Clifford which proposes using the same ester materials in a non-reactive, inert atmosphere.
The Wilson-type waterless dyeing compositions are said to include the use of various dyes or pigments as organic colorants in these waterless dye compositions. A wide variety of candidate dyes and pigments are identified in column 8 of this patent, as well as in column 13, lines 31-35 of the Clifford patent. These documents indicate that the choices of suitable dyes and pigments are extremely wide, and that results using any particular dye or pigment selected are comparable, one to the other. It has now been found that only a limited number of dyes meeting very stringent and diverse criteria are actually suitable and form a preferred class for dyeing synthetic fibers, notably nylons and polyesters.
The process of the present invention in one aspect features the use of solvent dyes dissolved in high-boiling ester solvents to color synthetic textiles, notably polyester and nylon. Relatively few dyes are soluble in these high-boiling organic ester materials. The common practice in the art has been to use a class of water-insoluble dyes known as disperse dyes, that is, dyes that are only dispersible rather than soluble in water. These dyes are the type exemplified in the Wilson patent noted above.